Docker builds redis3 master-slave cluster and expands the capacity

3 Lord 3 from Redis Cluster expansion and contraction

When using master-slave, it is necessary to avoid that the master and slave are on the same physical machine , Otherwise, when a master-slave pair hangs up , Corresponding data is unavailable

One . structure

1.  establish 6 individual Redis Container instance 
docker run -d --name redis-node-1 --net host --privileged=true -v /opt/redis/share/redis-node-1:/data redis --cluster-enabled yes --appendonly yes --port 6381
docker run -d --name redis-node-2 --net host --privileged=true -v /opt/redis/share/redis-node-2:/data redis --cluster-enabled yes --appendonly yes --port 6382
docker run -d --name redis-node-3 --net host --privileged=true -v /opt/redis/share/redis-node-3:/data redis --cluster-enabled yes --appendonly yes --port 6383
docker run -d --name redis-node-4 --net host --privileged=true -v /opt/redis/share/redis-node-4:/data redis --cluster-enabled yes --appendonly yes --port 6384
docker run -d --name redis-node-5 --net host --privileged=true -v /opt/redis/share/redis-node-5:/data redis --cluster-enabled yes --appendonly yes --port 6385
docker run -d --name redis-node-6 --net host --privileged=true -v /opt/redis/share/redis-node-6:/data redis --cluster-enabled yes --appendonly yes --port 6386
	#  Parameters,  --net host =  Using the host ip And port ,  Is the default option 

2.  Build clusters 
redis-cli --cluster create 10.122.1.86:6381 10.122.1.86:6382 10.122.1.86:6383 10.122.1.86:6384 10.122.1.86:6385 10.122.1.86:6386 --cluster-replicas 1		#  One by one 
yes
3.  View the cluster status (redis Internal execution )
cluster info		
cluster nodes	#  The corresponding relationship between master and slave can be determined 
M		S
1		6
2		4
3		5
redis-cli --cluster check 10.122.1.86:6381	( In container execution )

4. Connect to the cluster 
docker exec -it redis-node-1 /bin/bash
redis-cli -p 6381 -c

5.  Fault tolerant migration ,  If someone master Dang ,  Is there a slave Host 
 docker stop redis-node-2		#  Host execution 
 # check state 
cluster nodes 
 #  Find out master,fail,  Wait for a short time again check
cluster nodes
#  You will find that it belongs to master2 Of slave4 Host ,  become master

Two . Capacity expansion

demand : Add master-slave , master6387, Its slave by 6388

1.  Boot instance 
docker run -d --name redis-node-7 --net host --privileged=true -v /opt/redis/share/redis-node-7:/data redis --cluster-enabled yes --appendonly yes --port 6387
docker run -d --name redis-node-8 --net host --privileged=true -v /opt/redis/share/redis-node-8:/data redis --cluster-enabled yes --appendonly yes --port 6388
2.  take 6387 Node as master To join the cluster 
docker exec -it redis-node-7  /bin/bash
redis-cli  --cluster add-node 10.122.1.86:6387 10.122.1.86:6381
redis-cli  --cluster check 10.122.1.86:6381 Find out 6387 Already as new master
3.  Reassign slot numbers 

   How many slots do you want to move (from 1 to 16384)? 4096

   What is the receiving node ID?	c6822e309e97b70122ec8219334b28457bbd6845

   Source node #1: all

   Do you want to proceed with the proposed reshard plan (yes/no)? yes

   redis-cli  --cluster check 10.122.1.86:6381

#  Find out 6387 Nodes have 4096 Slots ( The original 3 Each node is evenly distributed )

1.  take 6388 As 6387 Of slave Add to cluster 
redis-cli --cluster add-node 10.122.1.86:6388 10.122.1.86:6387 --cluster-slave --cluster-master-id c6822e309e97b70122ec8219334b28457bbd6845
redis-cli -p 6381 -c
cluster nodes 	#  Confirm cluster status 

3、 ... and . Shrinkage capacity

demand : Delete master-slave 6387 and 6388

1.  Delete slave 6388
redis-cli --cluster del-node 10.122.1.86:6388 1da4941694c45812027fc74e687d7de17ad798eb
2.  Reallocate slots 
2.1  programme 1:  take 6387 The slot of is assigned to 6382
	 redis-cli  --cluster reshard 10.122.1.86:6382
	 How many slots do you want to move (from 1 to 16384)? 4096
	 What is the receiving node ID? 4314fd868093beea918b8aabacca74f3800855e4
	 Source node #1: c6822e309e97b70122ec8219334b28457bbd6845
	 Source node #2: done
	 Do you want to proceed with the proposed reshard plan (yes/no)? yes
	 

   		 redis-cli  --cluster check 10.122.1.86:6381

#  Find out 6387 There are no slots ,  and 6382 Yes 8192 Slots 

1.  Delete host 6387
redis-cli --cluster del-node 10.122.1.86:6387 c6822e309e97b70122ec8219334b28457bbd6845
2.  confirm 
redis-cli  --cluster check 10.122.1.86:6381